Bilateral Pupillary Involvement as a Clinical Presentation of Herpes Zoster Ophthalmicus.

Purpose: Herpes zoster ophthalmicus (HZO) is traditionally considered as an unilateral disease. However, subclinical involvements in the contralateral eye structures are evidence, giving rise to a broader understanding of varicella-zoster virus (VZV) infection. Methods: We enrolled 20 eyes of 10 patients with HZO and 12 eyes of healthy controls to investigate the bilateral features of HZO patients using a hand-held pupillometer and a Cochet-Bonnet esthesiometer. Results: Maximum pupil size before constriction (INT) and minimum diameter when pupil constricts at peak (END) were significantly smaller in patients affected eyes compared with those in controls (p < .05). Interestingly, INT and END were significantly reduced in contralateral eyes of 20 affected patients and also in comparison to control group (p < .001 and p = .034 respectively). Conclusion: The contralateral eyes may have subclinical involvement in patients with HZO based on significantly abnormal pupillary light reflex (PLR). Pupillometer provides a primary and convenient method to investigate the anatomy and pathology of the PLR.